Charles l



(No Model.)

G. L. BUGKINGHAM.

GOMMUTATOR.

Patented Dee. 4, 1.888.

(g1/noauto@ UNITED STATES PATENT OEEICE.

CHARLES L. BUCKINGHAM, OF NEV YORK, N. Y.

COMMUTATOR.

SPECIFICATION forming part of Letters Patent No. 394,095, dated December 4, 1888.

Application tiled October 5, 1888.

.To @ZZ whom it may concern:

Be it known that I, CHARLES L. BUCKING- HAM, of the city, county, and State ot' New York, a citizen of the United States ot' America, have made a new and usetul Improvement in Dynamo-Machines, its purpose being to avoid flashing at the commutator, which usually occurs when the machine is taxed to near its full generative capacity, ot which the following is a specitication.

Others have heretofore submerged the rotary commutator in a reservoir ot oil to overcome this difficulty; but in suoli arrangements the leakage of oil from the reservoir through the journal-bearing is a serious objection. lith my improvement l avoid submerging the entire commutator, and do not even raise the oil to the level of the lower side of the shaft.

ln commutators as ordinarily constructed there are a rotating' hub and two brushes yplaced opposite each other for collecting' current; but in suoli construction, it oil avere used, its level would have to be raised to cover the ends ot' both brushes, and consequently above the center otl the journal. l, however, propose to employ a commutator whose strips are so arranged that brushes arranged in the same angular position will make contact with diametrically-opposite coils of the armature. By thus constructing the commutator, instead of placing the brushes on opposite sides of the conunutator, they may both be placed in the same angular position, and both may make contact with the commutator at the lowest point of rotation, thereby necessitating small part of its peripheral surface.

Figure l represents an end sectional view of my improvement as applied to the opencircuit machine upon which four coils `are employed, there being two conmiutator-strips arranged diametrically opposite each other for each coil to which its ends are respectively joined. Fig. 2 represents a side view of the same device, partly in section. Fig. represents a single commutator-strip.

In Fig. 1,'m is a commutator-hub, the strips or sections being numbered from one to eight,

as shown, and each strip has at each end of the hub a wearing-section; but the two secl Serial No. 287,327. (No model.)

tions are arranged diametrically opposite each other, and are electrically joined together, as shown in Fig. El.

d and e are connnutator-lmarshes, cach having three strips electrically joined together, thereby aitording a continuous contact upon the commutator of about three-eighths of a circle. The tree ends ot each coil are joined, respectively, to diametrically-opposite commutator-st-rips. Thus the outer ends of one armature-coil are respectively joined to sections l and 5 ot the commutator. lt will now be seen that while one end ot the coil is in Contact with brush e through sect-ion l the other end of the coil is in connection with brush (l through section 5. As shown in Fig. l, a circuit through the armature from the positive to the negative pole is formed through brush e, conmuitator-sections l 2 3, the three corresponding armature-coils in multiple arc, commutator-sections 5 (i T, and brush (l. y this arrangement the armature-coils are joined with the brushes precisely as though the brushes were used ou opposite sides ot the commutator, for if the brush d were transferred along the shaft and placed opposite brush e it would occupy the saine position in respect to the coils ot the armature. XVith the commutator-stripsmadeas shown in Figs. 2 and 3 brushes d and e may be made to occupy the same angular position one with the other, and only oil enough need be placed in reservoir c to cover the range of contact between said brushes and hub, and it isuot necessary that the entire section of contact be covered, for, as is well known, it the commuonly the use of oil enough to cover a very;

tator be rotated in the direction indicated by the arrow, the tendency will be for the spark to be drawn almost entirely from the lower strip ot' each brush, wherefore it is only this part that requires to be covered with oil. ln case of commutators where only a single-strip brush is used and contact is confined to a single line parallel with the axis, as in the Gramme or Alleneck, it is even less important that more than a small part ot' the hub be submerged.

To prevent oil from being thrown out ot` the reservoir by the rapid rotation of the com` mutator, a shield, 7l, of insulating material, also serving as a scraper, is employcd,which IOO rests lightly upon Jhe hub at a level near Jghe 2. As a means of preventing flashing, the 1o top of the reservoir. Combination of a oommutatorand brushes What I claim, and desire to secure by Letand an oil-reservoir holding only suiioient oil ters Patent, isto cover the points of Contact between the 5 l. As a means for preventing ashing in brushes and oolninutators. 0

dynamo-machines, the Combination of a conl- CHARLES L. BUCKINGHAM. mutator-hub, an oil-reservoir, and two Witnesses: brushes occupying the saine or substantially JOHN C. SANDERS,

the saine angular position. A ARNOUX. 

